The primary objective of the proposed three-year study is to develop biochemical markers for diabetes mellitus in order to provide basis for designing noninvasive techniques for early diagnosis and thus more efficient control of the disorder. The markers will be isolated from expired air of 122 subjects including 50 prediabetics (potential, latent and asymptomatic diabetics), 36 overt diabetics and 36 control subjects. The isolation and characterization of the markers will be achieved by utilizing the recent pertinent development achieved at the IIT Research Institute. These developments include (a) novel techniques for quantitative collection and processing of expired air, (b) a special computer program for quantitative analysis of complex gas chromatographic patterns, and (c) a fundamental information on the composition of expired air for a representative group of normal healthy nondiabetic population. The final selection of the biochemical markers will be based on positive correlations between the analytical data and the glucose tolerance and insulin response curves. Physical and chemical properties of the selected markers will be considered to simplify the procedures required for the practical diagnostic application of the markers.